High refractive index, high abbe number intraocular lens materials

ABSTRACT

Disclosed are high refractive index, hydrophobic, acrylic materials. These materials have both high refractive index and a high Abbe number. This combination means the materials have a low refractive index dispersion and thus are especially suitable for use as intraocular lens materials. The materials are also suitable for use in other implantable ophthalmic devices, such as keratoprostheses, corneal rings, corneal implants, and corneal inlays.

FIELD OF THE INVENTION

This invention is directed to acrylic device materials. In particular,this invention relates to high refractive index acrylic device materialsparticularly suited for use as intraocular lens (“IOL”) materials, whichcan be injected through small incisions of less than 2.5 mm.

BACKGROUND OF THE INVENTION

With the recent advances in small-incision cataract surgery, increasedemphasis has been placed on developing soft, foldable materials suitablefor use in artificial lenses. In general, these materials fall into oneof three categories: hydrogels, silicones, and acrylics.

In general, hydrogel materials have a relatively low refractive index,making them less desirable than other materials because of the thickerlens optic necessary to achieve a given refractive power. Siliconematerials generally have a higher refractive index than hydrogels, buttend to unfold explosively after being placed in the eye in a foldedposition. Explosive unfolding can potentially damage the cornealendothelium and/or rupture the natural lens capsule. Acrylic materialsare desirable because they typically have a higher refractive index thansilicone materials and unfold more slowly or controllably than siliconematerials.

U.S. Pat. No. 5,290,892 discloses high refractive index, acrylicmaterials suitable for use as an IOL material. These acrylic materialscontain, as principal components, two aryl acrylic monomers. They alsocontain a cross-linking component. The IOLs made of these acrylicmaterials can be rolled or folded for insertion through small incisions.

U.S. Pat. No. 5,331,073 also discloses soft acrylic IOL materials. Thesematerials contain as principal components, two acrylic monomers whichare defined by the properties of their respective homopolymers. Thefirst monomer is defined as one in which its homopolymer has arefractive index of at least about 1.50. The second monomer is definedas one in which its homopolymer has a glass transition temperature lessthan about 22° C. These IOL materials also contain a cross-linkingcomponent. Additionally, these materials may optionally contain a fourthconstituent, different from the first three constituents, which isderived from a hydrophilic monomer. These materials preferably have atotal of less than about 15% by weight of a hydrophilic component.

U.S. Pat. No. 5,693,095 discloses foldable ophthalmic lens materialscomprising a total of at least 90% by weight of only two principallens-forming monomers. One lens-forming monomer is an aryl acrylichydrophobic monomer. The other lens-forming monomer is a hydrophilicmonomer. The lens materials also comprise a cross-linking monomer andoptionally comprise a UV absorber, polymerization initiators, reactiveUV absorbers and reactive blue-light absorbers.

U.S. Pat. No. 6,653,422 discloses foldable ophthalmic lens materialsconsisting essentially of a single device-forming monomer and at leastone cross-linking monomer. The materials optionally contain a reactiveUV absorber and optionally contain a reactive blue-light absorber. Thesingle device-forming monomer is present in an amount of at least about80% by weight. The device-forming monomer is an aryl acrylic hydrophobicmonomer.

Acrylic materials with a higher refractive index have historically beenpreferred as IOL materials because less material is required to make alens of a given dioptric power. Thus a lens made from a higherrefractive index material may be implanted through a smaller incisionthan a similar power lens made from a lower refractive index material.Use of a smaller incision in turn results in fewer traumas and reducesthe likelihood of surgically induced astigmatism. However, polymermaterials with high refractive index also generally exhibit refractiveindex dispersion. This can result in chromatic aberrations that mayimpact visual performance when viewing light of differing wavelengths.

In general, the presence of aromatic groups leads to materials withhigher refractive index dispersion. Hydrophobic acrylic materialswithout aromatic groups will have reduced refractive index dispersionbut will also have lower refractive index, thus will require a largerincision size than a comparable lens made from a high refractive indexpolymer.

SUMMARY OF THE INVENTION

Improved soft, foldable acrylic materials which are particularly suitedfor use as IOLs, but which are also useful as other implantableophthalmic devices, such as keratoprostheses, corneal rings, cornealimplants, and corneal inlays have now been discovered. These materialshave both high refractive index and low refractive index dispersion.This is accomplished using monomers containing cycloaliphatic functionalgroups in a hydrophobic acrylic polymer. The materials of the presentinvention are copolymers formed by polymerizing a mixture comprising amajor amount of a cycloaliphatic hydrophobic acrylic monomer, ahydrophilic monomer, and a cross-linking agent.

The implantable ophthalmic device materials of the present invention areoptically clear such that they are suitable for use as IOLs and theyhave low tack, low surface scatter, good stability profile, and gooddelivery properties. Among other factors, the present invention is basedon the finding that a multi-component, copolymeric, high refractiveindex device material obtained by copolymerizing the ingredientsmentioned above is soft, glistening-free, has low tack and low haze, haslow surface light scatter, and is capable of going through small (2.5 mmor less) incisions with good unfolding properties.

DETAILED DESCRIPTION OF THE INVENTION

Unless indicated otherwise, all component amounts are presented on a %(w/w) basis (“wt. %”).

The ophthalmic device materials of the present invention comprise amajor amount of a cycloaliphatic acrylic monomer having the formula:

wherein: A is H or CH₃;

B is O, NR, or S;

D is O, S, or nothing (i.e., a single bond);

E is CH₃, CH₂CH₃, CH(CH₃)₂, C(CH₃)₃, CH₂OH or H;

R is H, CH₃, CH₂CH₃, or CH(CH₃)₂;

x is 1-4, provided that if x is >1, then not more than one CHE group hasE≠H;

y is 0-2; and

z is 0-4, provided that if D=nothing, then z≠0.

Preferred acrylic hydrophobic monomers for use in the materials of thepresent invention are those wherein B is O, z is 0-2, D is O or nothing,y is 0, x is 2 or 3, and E is independently H, CH₂OH or CH₃, provided ifz=0 or 1, then D is nothing. Most preferred is B is O, z is 2, D isnothing, y is 0, x is 3, and E is H. For example, preferred monomersinclude 2-cyclohexylethyl acrylate, 2-cyclopentylethyl acrylate,3-cyclohexylpropyl acrylate, 3-cyclopentylpropyl acrylate and2-(cyclohexyloxy)ethyl acrylate. Most preferred is 2-cyclohexylethylacrylate.

Monomers of formula I can be made by known methods. For example, theconjugate alcohol of the desired monomer can be combined in a reactionvessel with methyl acrylate, tetrabutyl titanate (catalyst), and apolymerization inhibitor such as 4-benzyloxy phenol. The vessel can thenbe heated to facilitate the reaction and distill off the reactionby-products to drive the reaction to completion. Alternative synthesisschemes involve adding acrylic acid to the conjugate alcohol andcatalyzing with a carbodiimide or mixing the conjugate alcohol withacryloyl chloride and a HCI acceptor such as pyridine or triethylamine.

The monomeric mixture polymerized to obtain the materials of the presentinvention comprises a total of 70-90%, preferably 75-85%, and morepreferably 77-82% one or more monomers of formula (I).

In addition to the monomer of formula (I), the mixture polymerized toform the materials of the present invention also contains a hydrophilicmonomer selected from the group consisting of: hydroxy(C₂-C₄alkyl)methacrylates, glycerol methacrylate, and N-vinyl pyrrolidone.Hydroxy(C₂-C₄ alkyl)methacrylates are preferred. The most preferredhydrophilic monomer is 2-hydroxyethyl methacrylate. The mixture orsolution to be polymerized will contain a total amount of hydrophilicmonomer of 5-25%, preferably 12-22%, and more preferably 16-19%. Thetotal amount of hydrophilic monomers contained in the materials of thepresent invention should be limited such that the equilibrium watercontent (at 35° C.) of the polymerized device material of the presentinvention is less than 4%, and preferably less than 2%.

The copolymer materials of the present invention are cross-linked. Thecopolymerizable cross-linking agent used in the copolymers of thisinvention may be any terminally ethylenically unsaturated compoundhaving more than one unsaturated group. Suitable cross-linking agentsinclude, for example low molecular weight cross-linking agents having amolecular weight from 100-500 Daltons and high molecular weightcross-linking agents having a molecular weight from 501-6,000 Daltons.Low molecular cross-linking agents will typically be present in a totalamount from 0.5-3%, whereas high molecular weight cross-linking agentswill typically be present in a total amount from 2-15%. In general, thetotal amount of cross-linking agent in the materials of the presentinvention will range from 0.5-10%, and will preferably range from 1-3%of low molecular weight cross-linker or 3-10% of a high molecular weightcross-linker.

Suitable low molecular weight cross-linking agents include: ethyleneglycol diacrylate; diethylene glycol diacrylate; allyl acrylate;1,3-propanediol diacrylate; 2,3-propanediol diacrylate; 1,6-hexanedioldiacrylate; 1,4-butanediol diacrylate; triethylene glycol diacrylate;cyclohexane-1,1-diyldimethanol diacrylate, 1,4-cyclohexanedioldiacrylate, 1,3-adamantanediol diacrylate, 1,3-adamantanedimethyldiacrylate, 2,2-diethyl-1,3-propanediol diacrylate,2,2-diisobutyl-1,3-propanediol diacrylate, 1,3-cyclohexanedimethyldiacrylate, 1,4-cyclohexanedimethyl diacrylate; neopentyl glycoldiacrylate; and their corresponding methacrylates. Preferred lowmolecular cross-linking monomers include 1,4-butanediol diacrylate;1,4-cyclohexanedimethyl diacrylate; and neopentyl glycol diacrylate.Most preferred is neopentyl glycol diacrylate. Suitable high molecularweight cross-linking agents include poly(ethylene glycol) dimethacrylate(M_(n)=700 Daltons) and poly(ethylene glycol) dimethacrylate (M_(n)=2000Daltons).

In a preferred embodiment, the mixture used to form the materials of thepresent invention contains 0.5-2%, preferably 1.4-1.8%, neopentyl glycoldiacrylate.

In addition to the monomer of formula (I), the hydrophilic monomer, andthe cross-linking agent, the mixture used to form the materials of thepresent invention preferably also contains a reactive (polymerizable) UVabsorber and optionally contains a reactive blue-light absorber.

Many reactive UV absorbers are known. Preferred reactive UV absorbersare 2-(2′-hydroxy-3′-methallyl-5′-methylphenyl)benzotriazole,commercially available as o-Methallyl Tinuvin P (“oMTP”) fromPolysciences, Inc., Warrington, Pa.,3-(2H-benzo[d][1,2,3]triazol-2-yl)-4-hydroxyphenylethyl methacrylate,and2-(3-(tert-butyl)-4-hydroxy-5-(5-methoxy-2H-benzo[d][1,2,3]triazol-2-yl)phenoxy)ethylmethacrylate. UV absorbers are typically present in an amount from 0.1-5wt. %. In one embodiment, the materials of the present invention contain1.5-2.5 wt. %, preferably 1.5-2 wt. %, of a reactive UV absorber.

Many reactive blue-light absorbing compounds are known. Preferredreactive blue-light absorbing compounds are those described in U.S. Pat.Nos. 5,470,932; 8,207,244; and 8,329,775, the entire contents of whichare hereby incorporated by reference. A preferred blue-light absorbingdye is N-2-[3-(2′-methylphenylazo)-4-hydroxyphenyl]ethyl methacrylamide.When present, blue-light absorbers are typically present in an amountfrom 0.005-1 wt. %, preferably 0.01-0.1 wt. %.

Although the monomer mixture that is polymerized to form the ophthalmicdevice materials of the present invention contains a monomer of formula(I), a hydrophilic monomer, a cross-linking agent, preferably contains aUV absorber, and optionally contains a blue-light absorber, itpreferably does not contain any aromatic monomer.

The implantable ophthalmic device materials of the present invention areprepared by combining the ingredients described above and polymerizingthe resulting mixture. Suitable polymerization initiators includethermal initiators and photoinitiators. Preferred thermal initiatorsinclude peroxy free-radical initiators, such as t-butyl(peroxy-2-ethyl)hexanoate; and di-(tert-butylcyclohexyl)peroxydicarbonate (commercially available as Perkadox® 16 from AkzoChemicals Inc., Chicago, Ill.), or azo initiators, such as2,2′-(diazene-1,2-diyl)bis(2,4-dimethylpentanenitrile. A preferredphotoinitiator is phenylphosphorylbis(mesitylmethanone), which iscommercially available as Irgacure® 819. Initiators are typicallypresent in an amount of 3 wt. % or less, and preferably 1.5 wt. % orless. Customarily, the total amount of initiator is not included whendetermining the amounts of other ingredients in copolymericcompositions.

The identity and amount of the principal monomer component (the monomerof formula (I)) described above and the identity and amount of anyadditional components are determined by the desired properties of thefinished ophthalmic lens material. Preferably, the ingredients and theirproportion are selected so that the acrylic device materials of thepresent invention possess the following properties, which make thematerials of the present invention particularly suitable for use in IOLswhich are to be inserted through incisions of 2.5 mm or less, andpreferably 2.0 mm or less.

The lens material preferably has a refractive index of 1.46-1.50,preferably 1.48-1.50, and most preferably 1.49-1.50. Despite having arelatively high refractive index, the materials of the present inventionhave an Abbe No. greater than 47, preferably greater than 50, and mostpreferably, greater than 52. Refractive index and Abbe No. are bothmeasured using an Abbe refractometer and a material sample that has beenequilibrated in balanced salt solution at 35° C. prior to measurement.Refractive index measurements are taken at 589 nm (Na light source). TheAbbe number (v_(D)) is calculated using the following formula:

d D=(n _(D)−1)/(n _(F) −n _(C))

where n_(D), n_(F), and n_(C) are the refractive indices of the materialat 589 nm (sodium D), 486 nm (hydrogen F), and 656 nm (hydrogen C),respectively

The glass-transition temperature (“Tg”) of the lens material, whichaffects the material's folding and unfolding characteristics, ispreferably below about 15° C., and more preferably below about 10° C. Tgis measured by differential scanning calorimetry at 10° C./min., and isdetermined as the half-height of the heat capacity increase.

The lens material will have an elongation (strain at break) of at least110%, preferably at least 120%, and most preferably at least 130%. Thisproperty indicates that the lens generally will not crack, tear or splitwhen folded. Elongation of polymer samples is determined on dumbbellshaped tension test specimens with a 20 mm total length, length in thegrip area of 11 mm, overall width of 2.49 mm, 0.833 mm width of thenarrow section, a fillet radius of 8.83 mm, and a thickness of 0.9 mm.Testing is performed on samples at either 18±2° C. or 23±2° C. and50±10% relative humidity using a tensile tester. The grip distance isset at 11 mm and a crosshead speed is set at 50-mm/minute and the sampleis pulled to failure. The strain at break is reported as a fraction ofthe displacement at failure to the original grip distance. Stress atbreak is calculated at the maximum load for the sample, typically theload when the sample breaks, assuming that the initial area remainsconstant. The Young's modulus is calculated from the instantaneous slopeof the stress-strain curve in the linear elastic region. The 25% secantmodulus is calculated as the slope of a straight line drawn on thestress-strain curve between 0% strain and 25% strain. The 100% secantmodulus is calculated as the slope of a straight line drawn on thestress-strain curve between 0% strain and 100% strain.

The lens material will have an equilibrium water content (EWC) of lessthan <4%. EWC is gravimetrically determined using an analytical balance.First, the dry sample weight is obtained, then the sample isequilibrated in balanced salt solution (BSS) at ambient temperature forat least 24 h. The sample is then removed from the BSS, excess surfaceliquid is removed and the sample is weighed. % EWC is determined by thefollowing formula:

${\% \mspace{14mu} {EWC}} = {\frac{\left( {{wt_{hydrated}} - {wt_{dry}}} \right)}{wt_{hydrated}} \times 100}$

Glistening evaluation was carried out by placing samples in deionizedwater at 45° C. for 20 hours. The samples are then transferred to a 37°C. bath Samples were inspected for glistenings after 2 hours of coolingto 37° C. using an optical microscope under dark field conditions with amagnification of at least 100×. The average number of glistenings permm² in the sample is determined. Preferably, the materials of thepresent invention have less than 10 glistenings/mm², and more preferablyless than 1 glistening/mm².

IOLs constructed of the materials of the present invention can be of anydesign capable of being rolled or folded into a small cross section thatcan fit through a relatively smaller incision. For example, the IOLs canbe of what is known as a one piece or multipiece design, and compriseoptic and haptic components. The optic is that portion which serves asthe lens. The haptics are attached to the optic and hold the optic inits proper place in the eye. The optic and haptic(s) can be of the sameor different material. A multipiece lens is so called because the opticand the haptic(s) are made separately and then the haptics are attachedto the optic. In a single piece lens, the optic and the haptics areformed out of one piece of material. Depending on the material, thehaptics are then cut, or lathed, out of the material to produce the IOL.

The invention will be further illustrated by the following examples,which are intended to be illustrative, but not limiting.

EXAMPLES

Monomer solutions were prepared by combining ingredients in proportionsas listed in Tables 1-4 below. Each solution was thoroughly mixed andbubbled with N₂. The monomer solution was filtered through a 0.2 micronPTFE membrane directly into polypropylene lens molds or rectangular flatmolds. For Examples 1-5, the filled molds were placed in an oven andheated to 70° C. for 1 hr, followed by a 2 hr post cure at 100° C. Oncecooled, the product was removed from the molds, extracted in acetone atambient temperature, rinsed with fresh acetone and allowed to air dry.The product was then placed under vacuum at 70° C. for at least 16 h.For Examples 6-22, the filled molds were placed in a preheated 105° C.oven for 20 min, followed by a 2 hr 40 min post cure at 100° C. Oncecooled, the product was removed from the molds, extracted in ethanol atambient temperature, rinsed with fresh ethanol and allowed to air dry.The product was then placed under vacuum at 80° C. for at least 16 h.Prior to delivery testing the IOL samples were Argon plasma treated for1 min (400 W, 160 mTorr) to reduce tackiness (see, e.g., U.S. Pat. No.5,603,774). Tensile properties, refractive index, Abbe no., glistenings,and EWC were determined as described above. Tensile properties weremeasured using an Instron Material Tester Model No. 4442 with a 50 Nload cell using a crosshead speed of 50 mm/min. Refractive index andAbbe number were measured using an ATAGO DR-M2 multi-wavelength Abberefractometer.

TABLE 1 Examples 1-5 EX 1 EX 2 EX 3 EX 4 EX 5 CHEA (wt. %) 81.62 76.5778.54 78.23 78.40 HEMA (wt. %) 15.03 20.07 18.07 18.03 18.09 BDDA (wt.%) 1.55 1.56 1.63 — — CHDA (wt. %) — — — 1.92 — NPGDA (wt. %) — — — —1.69 oMTP (wt. %) 1.80 1.80 1.75 1.81 1.82 Perkdox16 (wt. % of 1.00 0.990.99 0.99 1.01 total formulation) RI (BSS, 35° C.) 1.497 1.496 — 1.4971.497 Abbe No (BSS, 35° C.) 55.2 ± 0.0  57.9 ± 4.7  — 55.4 ± 1.0  54.7 ±2.1  EWC (BSS, 23° C.) 0.72 ± 0.10 1.63 ± 0.05 0.84 1.14 ± 0.16 0.88 ±0.08 Glistenings (MV/mm²) <5 <1 <1 <10 <1 T_(g, start) (° C.) −12.5 −8.4−7.4 −7.1 −6.2 T_(g, mid) (° C.) −7.0 −3.9 −2.9 −2.1 −1.5 T_(g, end) (°C.) −1.6 0.7 1.6 2.8 3.1 Stress at Break (MPa) 1.64 ± 0.21 4.88 ± 0.403.22 ± 0.33 3.28 ± 0.28 3.81 ± 0.29 Strain at Break (%) 137.2 ± 7.7 140.1 ± 4.2  141.4 ± 5.8  132.1 ± 6.9  161.3 ± 6.7  Young's Modulus(MPa) 11.55 ± 2.33  34.14 ± 4.29  19.10 ± 1.57  22.35 ± 2.58  21.02 ±2.69  25% Secant Modulus 1.37 ± 0.05 4.76 ± 0.59 2.59 ± 0.05 2.83 ± 0.132.69 ± 0.10 100% Secant Modulus 1.01 ± 0.03 3.36 ± 0.40 1.90 ± 0.04 2.16± 0.07 1.89 ± 0.02 Instron test temp (° C.) 24.5 24.3 24.4 24.6 24.6CHEA = 2-cyclohexylethyl acrylate HEMA = 2-hydroxyethyl methacrylateBDDA = 1,4-butanediol diacrylate CHDA = 1,4-cyclohexanediemthyldiacrylate NPGDA = neopentyl glycol diacrylate oMTP =2-(2′-hydroxy-3′-methallyl-5′-methylphenyl)benzotriazole Perkadox16 =Di(4-tert-butylcyclohexyl) peroxydicarbonate

TABLE 2 Examples 6-10 EX 6 EX 7 EX 8 EX 9 EX 10 CHEA (wt. %) 78.78 78.3878.58 78.58 78.58 HEMA (wt. %) 18.00 18.00 18.00 18.00 18.00 NPGDA (wt.%) 1.62 1.62 1.62 1.62 1.62 oMTP (wt. %) 1.60 2.00 1.80 1.80 1.80Perkdox16 (wt % of 1.50 1.50 1.75 1.25 1.50 total formulation) Young'smodulus (MPa) 89.79 ± 5.10 105.38 ± 9.83  103.44 ± 8.24  96.91 ± 4.79103.7 ± 8.36 Secant modulus, 25% (MPa) 10.28 ± 0.36 11.34 ± 0.26 11.35 ±0.24 11.05 ± 0.15 10.93 ± 0.35 Secant modulus, 100% (MPa)  5.02 ± 0.16 5.32 ± 0.10  5.39 ± 0.12  5.16 ± 0.06  5.15 ± 0.18 Tensile strength(MPa)  9.89 ± 0.89  9.90 ± 1.34  9.61 ± 0.91  9.40 ± 0.96  9.88 ± 0.79Strain at break (%) 184.7 ± 11.5 179.4 ± 17.0 177.0 ± 10.7 180.4 ± 12.3189.7 ± 12.9

TABLE 3 Examples 11-16 EX 11 EX 12 EX 13 EX 14 EX 15 EX 16 CHEA 80.8080.58 80.40 79.80 79.58 79.40 HEMA 16.00 16.00 16.00 17.00 17.00 17.00NPGDA 1.40 1.62 1.80 1.40 1.62 1.80 oMTP 1.80 1.80 1.80 1.80 1.80 1.80Secant modulus 6.28 ± 7.04 ± 7.32 ± 7.58 ± 8.28 ± 8.71 ± (25%) 0.15 0.280.26 0.11 0.32 0.26 Secant modulus 3.28 ± 3.62 ± 3.90 ± 3.81 ± 4.20 ±4.48 ± (100%) 0.06 0.14 0.15 0.05 0.14 0.14 Tensile strength 7.23 ± 6.42± 7.81 ± 8.58 ± 7.87 ± 7.96 ± 0.41 0.98 1.13 0.49 0.63 1.01 % Strain atbreak 184 ± 168 ± 172 ± 189 ± 170 ± 166 ± 6 20 12 5 7 13 SSNG 17.2 ±17.1 ± 10.1 ± 14.4 ± 20.4 ± 8.9 ± (PBS, n = 5) 3.2 6.2 2.1 2.9 5.6 2.0Glistening density 0.1 ± 0.1 ± 0.1 ± 0.1 ± 0 0 (vac/mm²) 0.3 0.4 0.4 0.3

TABLE 4 Examples 17-22 EX 17 EX 18 EX 19 EX 20 EX 21 EX 22 CHEA 78.8078.58 78.40 77.80 77.58 77.40 HEMA 18.00 18.00 18.00 19.00 19.00 19.00NPGDA 1.40 1.62 1.80 1.40 1.62 1.80 oMTP 1.80 1.80 1.80 1.80 1.80 1.80Secant modulus 9.50 ± 10.07 ± 11.13 ± 11.94 ± 12.54 ± 11.62 ± (25%) 0.500.38 0.29 0.30 0.31 0.59 Secant modulus 4.61 ± 4.97 ± 5.50 ± 5.54 ± 5.92± 5.67 ± (100%) 0.19 0.20 0.12 0.15 0.09 0.22 Tensile strength 8.88 ±8.44 ± 9.02 ± 8.91 ± 9.28 ± 9.16 ± 0.86 0.66 0.52 1.12 0.73 0.56 %Strain at break 184 ± 166 ± 161 ± 166 ± 157 ± 158 ± 15 5 9 7 8 6 SSNG21.7 ± 16.6 ± 9.7 ± 15.2 ± 12.9 ± 12.8 ± (PBS, n = 5) 1.6 9.1 5.7 1.23.1 5.4 Glistening density ND 0.1 ± ND ND ND ND (vac/mm²) 0.3

Example 23 Delivery Evaluation of Lenses

Lenses cast in 40 Diopter molds from select formulations were deliveredthrough Monarch III D cartridges using H4 handpieces (with and withoutsoft tip) and Viscoat viscoelastic. Lens delivery was carried out at 18°C. and 23° C. with no dwell time. Post-delivery evaluations includedoptic and haptic damage as well as delivery cartridge damage. Ingeneral, all the lens optics unfolded quickly and haptics did not stickto the optic region upon delivery. In addition, optics, haptics, anddelivery cartridges passed post-delivery cosmetic inspection.

The invention having now been fully described, it should be understoodthat it may be embodied in other specific forms or variations withoutdeparting from its spirit or essential characteristics. Accordingly, theembodiments described above are to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are intended to be embraced therein.

1. A polymeric ophthalmic device material made by polymerizing a mixtureof monomers wherein the mixture comprises: a) a total of 70-90 wt. % ofone or more cycloaliphatic acrylic monomers of formula (I)

wherein: A is H or CH₃; B is O, NR, or S; D is O, S, or nothing; E isCH₃, CH₂CH₃, CH(CH₃)₂, C(CH₃)₃, CH₂OH or H; R is H, CH₃, CH₂CH₃, orCH(CH₃)₂ x is 1-4, provided that if x is >1, then not more than one CHEgroup has E≠H; y is 0-2; and z is 0-4, provided that if D=nothing, thenz≠0; b) a total of 5-25 wt. % of one or more hydrophilic monomersselected from the group consisting of: hydroxy(C₂-C₄alkyl)methacrylates, glycerol methacrylate, and N-vinyl pyrrolidone; andc) a copolymerizable cross-linking agent; wherein the ophthalmic devicematerial has a refractive index of 1.46-1.50, an Abbe number greaterthan 47, and a T_(g)<10° C., and wherein the equilibrium water contentof the polymerized ophthalmic device material is less than 2%.
 2. Theophthalmic device material of claim 1 wherein for the cycloaliphaticacrylic monomer of formula (I): A is H or CH₃, B is O; D is O ornothing; E is CH₃ or H; x is 2 or 3, provided that not more than one CHEgroup has E =CH₃, y is 0; and z is 0-2, provided that if D=nothing, thenz≠0.
 3. The ophthalmic device material of claim 2 wherein for thecycloaliphatic acrylic monomer of formula (I): A is H or CH₃; B is O; Dis nothing; E is H; x is 3; y is 0; and z is
 2. 4. The ophthalmic devicematerial of claim 1 wherein the cycloaliphatic acrylic monomer offormula (I) is selected from the group consisting of: 2-cyclohexylethylacrylate; 2-cyclopentylethyl acrylate; 3-cyclohexylpropyl acrylate;3-cyclopentylpropyl acrylate; and 2-(cyclohexyloxy)ethyl acrylate. 5.The ophthalmic device material of claim 1 wherein the mixture comprisesa total of 75-85 wt. % of cycloaliphatic acrylic monomer of formula (I).6. The ophthalmic device material of claim 5 wherein the mixturecomprises a total of 77-82 wt. % of cycloaliphatic acrylic monomer offormula (I).
 7. The ophthalmic device material of claim 1 wherein thehydrophilic monomer is a hydroxy(C₂-C₄ alkyl)methacrylate and themixture comprises a total of 12-22 wt. % of hydrophilic monomer.
 8. Theophthalmic device material of claim 7 wherein the hydrophilic monomer is2-hydroxethyl methacrylate.
 9. The ophthalmic device material of claim 8wherein the mixture comprises a total of 16-19 wt. % of 2-hydroxethylmethacrylate.
 10. (canceled)
 11. (canceled)
 12. The ophthalmic devicematerial of claim 1 wherein the copolymerizable cross-linking agent is aterminally ethylenically unsaturated compound having more than oneunsaturated group.
 13. The ophthalmic device material of claim 12wherein the copolymerizable cross-linking agent is selected from thegroup consisting of: ethylene glycol diacrylate; diethylene glycoldiacrylate; allyl acrylate; 1,3-propanediol diacrylate; 2,3-propanedioldiacrylate; 1,6-hexanediol diacrylate; 1,4-butanediol diacrylate;triethylene glycol diacrylate; cyclohexane-1,1-diyldimethanoldiacrylate, 1,4-cyclohexanediol diacrylate, 1,3-adamantanedioldiacrylate, 1,3-adamantanedimethyl diacrylate,2,2-diethyl-1,3-propanediol diacrylate, 2,2-diisobutyl-1,3-propanedioldiacrylate, 1,3-cyclohexanedimethyl diacrylate, 1,4-cyclohexanedimethyldiacrylate; neopentyl glycol diacrylate; ethylene glycol dimethacrylate;diethylene glycol dimethacrylate; allyl methacrylate; 1,3-propanedioldimethacrylate; 2,3-propanediol dimethacrylate; 1,6-hexanedioldimethacrylate; 1,4-butanediol dimethacrylate; triethylene glycoldimethacrylate; cyclohexane-1,1-diyldimethanol dimethacrylate,1,4-cyclohexanediol dimethacrylate, 1,3-adamantanediol dimethacrylate,1,3-adamantanedimethyl dimethacrylate, 2,2-diethyl-1,3-propanedioldimethacrylate, 2,2-diisobutyl-1,3-propanediol dimethacrylate,1,3-cyclohexanedimethyl dimethacrylate, 1,4-cyclohexanedimethyldimethacrylate; neopentyl glycol dimethacrylate; poly(ethylene glycol)dimethacrylate (M_(n)=700 Daltons) and poly(ethylene glycol)dimethacrylate (M_(n)=2000 Daltons).
 14. The ophthalmic device materialof claim 1 wherein the mixture comprises a total of 0.5-10 wt. % ofcross-linking agent.
 15. The ophthalmic device material of claim 13wherein the mixture comprises 0.5-2 wt. % neopentyl glycol diacrylate.16. The ophthalmic device material of claim 1 wherein the mixturecomprises 0.1-5 wt. % of a reactive UV absorber.
 17. The ophthalmicdevice material of claim 1 wherein the ophthalmic device material has anAbbe number greater than
 50. 18. (canceled)
 19. An ophthalmic devicematerial made by polymerizing a mixture of monomers wherein the mixturecomprises: a) 75-85 wt. % 2-cyclohexylethyl acrylate; b) 12-22 wt. %2-hydroxethyl methacrylate; and c) 1-3 wt. % of a cross-linking agenthaving a molecular weight of 100-500 Daltons; wherein the ophthalmicdevice material has a refractive index of 1.48-1.50, an Abbe numbergreater than 52, a Tg<10 ° C., and an equilibrium water content lessthan 2%.
 20. (canceled)